Hybrid coupled damper for the mitigation of torsional vibrations and rotational irregularities in an automotive crankshaft: Concept and design subtleties

Abstract

This paper presents a new configuration to tackle a twofold problem affecting a crankshaft: the torsional vibrations and the oscillation of the speed at the back end of the shaft due to the torque ripples created by the cylinders. These two phenomena already have industrial solutions, but the requirement levels increase and impose constant improvements. Moreover, the common vibration dampers rely on energy dissipation as heat, which in a context of waste reduction could be avoided. This concept relies on the association of an optimal passive mechanical damper, an electric circuit and electromechanical converters, without any external power supply, in order to ensure a safe operation. From a more fundamental point of view, these elements link a time-periodic correction and a nonstationary cyclic excitation. The core idea of the concept is to enable a redistribution of the energy within this coupled electromechanical circuit, where each element can behave as a power consumer or supplier, so that the oscillations of the mechanical elements can be decreased. In this paper, the authors describe and model this new concept in order to investigate the resulting dynamic behavior and the key design parameters that affect the damping performance.